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Max Entropy Sampling favors the lower limit

burakbagdatli
Level III

When I create small maximum entropy designs, I get unbalanced distributions for the variables. It's mostly regular and with some extra points at the ends; however, the lower end is sampled much more frequently than any other point. I have tried it many times and attached a few examples to this message. If needed, I can provide more.

 

X1_Discrete.png

As you can see from the screenshot above, -1 is sampled must more frequently than any other value. Even with a continuous distribution it's clear that the lower limit is sampled more frequently:

X1_Continuous.png

However, it doesn't always happen. Unfortunately, in my experience, it happens more often than not. I have attached a few designs where the issue appears and disappears.

What we see of the real world is not the unvarnished real world but a model of the real world, constructed so it is useful for dealing with the real world. —Richard Dawkins
1 REPLY 1

Re: Max Entropy Sampling favors the lower limit

It is very difficult to assess the design one factor at a time. The solution must satisfy a multivariate criterion. Looking at two factors at a time, still short of all 20 factors, shows a smoother spread of runs.

 

matrix.PNG

 

If you believe that there is a problem with your design, you should reach out to JMP Technical Support (support@jmp.com) for resolution. If so, please reply with their findings and your conclusion.